void main() {
    //自动类型转换
    int a = 100;
    long b = a;
    float c = b;
    System.out.println(c);

    //强制类型转换与精度丢失
    double x = 3.14159;
    int y = (int) x;
    byte z = (byte) 130;
    System.out.println("y = " + y);
    System.out.println("z = " + z);

    //表达式中的类型提升
    short s1 = 10;
    short s2 = 20;
    int s3 = s1+ +s2;
    System.out.println(s3);
}